JP2004218875A - Parent-child burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the combustion performance and to smoothly move the flame between a parent burner and a child burner. <P>SOLUTION: The parent burner 3 is an inward burner port burner, the child burner 4 is an outward burner port burner, and the child burner 4 is mounted inside of the parent burner 3, so that they are opposite to each other. Whereby the fire can be smoothly transferred between the parent burner 3 and the child burner 4. Accordingly, an ignition electrode 11 is mounted only one of the burners (mounted at the child burner 4 side in an embodiment), and the manufacturing cost of the parent burner 99 can be reduced. Further as the parent burner 3 is the inward burner port burner, and the child burner 4 is the outward burner port burner, burner port faces are kept into contact with each other in a passage of the secondary air A for combustion, both burners 3, 4 can easily take the secondary air, and the combustion performance can be improved. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a parent-child burner including a large-fired parent burner and a small-fired child burner.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a gas stove in which an air-fuel mixture chamber is formed in an annular shape and provided with an inward burner burner in which a plurality of burners are arranged in an inner peripheral surface thereof (for example, see Patent Document 1).
In such a gas stove 101, as shown in FIG. 7, an inward flame port burner 103 is arranged at a center position of an opening 102a formed in a top plate 102, and a juice tray 106 is placed around the burner 103. The cooking pot P is placed on the goto 105 provided around the inward burner burner 103 and is heated by the combustion of the inward burner burner 103.
[0003]
The inward flame burner 103 has a large number of flames in a burner main body 103b to which fuel gas and primary air are supplied and an inner peripheral central cylinder 103a which is removably mounted coaxially on the head of the burner main body 103b. And an annular burner head 103c in which 151 are arranged. The burner main body 103b includes a mixing pipe section 120 into which the fuel gas is supplied from the nozzle 107 and mixed with the primary air, and a main body section 130 serving as a mounting section for the burner head 103c.
In the inward flame outlet burner 103, the mixed gas of the fuel gas and the primary air mixed in the mixing pipe portion 120 is guided to the ring-shaped main body portion 130, and the flames arranged in the central cylinder 103a of the burner head 103c are arranged. It spouts from the mouth 151. Then, the secondary air is sucked from below the central cylinder 103a, and a flame is formed toward the center of the inward flame port burner 103 to heat the cooking pot P.
In the gas stove 101 provided with such an inward flame outlet burner 103, since the flame is formed toward the center of the cooking pot P, the flame can be prevented from overflowing to the outside of the cooking pot P and used safely. it can.
[0004]
However, since the inward-facing burner burner 103 as described above burns fuel gas inside the burner head 103c, a large number of burners are provided on the outer peripheral surface of a generally used annular mixture chamber to secure a combustion space. It is inevitably larger than an outwardly-facing burner burner provided with a flame outlet.
When the burner outer diameter is large, as shown in FIG. 8, the contact area between the flame and the cooking pot is smaller than in the case where the burner outer diameter is small, causing a problem that the thermal efficiency is deteriorated.
[0005]
Therefore, in a large cooking stove used for business or the like, as shown in FIG. 9, a small-diameter child-facing burner burner 202 is arranged inside a large-diameter parent-facing burner burner 201, so that the bottom of the pan is reduced. A parent-child burner 200 has been developed in which the flame efficiency can be improved by enabling direct flame irradiation to the center (for example, see Patent Document 2).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-4852 [Patent Document 2]
JP 10-267228 A
[Problems to be solved by the invention]
However, in the parent-child burner 200 as described above, since both the large-diameter parent burner 201 and the small-diameter child burner 202 are inward-facing burner burners, there is a problem that it is difficult to set fire between the parent burner 201 and the child burner 202. there were. For this reason, each of the parent burner 201 and the child burner 202 must be provided with an igniter, leading to an increase in cost.
In addition, a gap is provided between the parent burner 201 and the child burner 202 to take in the secondary air from between the parent burner 201 and the child burner 202. Since the secondary air cannot be brought into contact with the air flow path, it is difficult to take in the secondary air, resulting in poor combustion. Further, the combustion performance is further deteriorated because the bottom surface of the central cylinder where the flame outlet of the child burner 202 is formed is sealed.
An object of the present invention is to solve the above-described problems, improve the combustion performance, and perform a good fire transfer between the parent burner and the child burner.
[0008]
[Means for Solving the Problems]
The parent-child burner according to claim 1 of the present invention which solves the above-mentioned problems,
In a parent-child burner including a large-fire parent burner and a small-fire child burner,
The parent burner forms an annular air-fuel mixture chamber, and blasts the air-fuel mixture from a number of flame ports arranged in an inner peripheral surface of the air-fuel mixture chamber. An inward burner burner that takes in secondary air,
The child burner is an outwardly directed flame burner in which a number of flames are radially arranged on the outer peripheral side, and is arranged in the secondary air passage surrounded by the air-fuel mixture chamber of the parent burner. The gist is that the upper end of the flame port of the child burner is lower than the lower end of the flame port of the parent burner.
[0009]
The parent-child burner according to claim 2 of the present invention is the parent-child burner according to claim 1,
The gist is that the height distance between the lower end of the flame port of the parent burner and the upper end of the flame port of the child burner is 10 mm to 30 mm.
[0010]
Further, the parent-child burner according to claim 3 of the present invention is the parent-child burner according to claim 1 or 2,
A thermal power control device for controlling the thermal power,
The gist of the present invention is to provide a gas amount adjusting means for adjusting only the amount of gas supplied to the parent burner without changing the amount of gas supplied to the child burner by the operation of adjusting the thermal power by the thermal power adjusting operation device.
[0011]
The parent-child burner according to claim 4 of the present invention is the parent-child burner according to claim 3,
The amount of gas supplied to the parent burner decreases as the thermal power is reduced by the thermal power control device, and when the thermal power is adjusted to the minimum thermal power, the gas supply to the parent burner is stopped. I do.
[0012]
The parent-child burner according to claim 1 of the present invention having the above configuration is an inward-facing burner burner in which a large-diameter parent burner ejects a flame inward, and a child burner provided inside the parent burner emits a flame. It is an outward flame burner that gushes outward. For this reason, the flame from the parent burner and the flame from the child burner are blown out facing each other, so that a good fire transfer is performed between the parent burner and the child burner.
Furthermore, since the child burner is provided at a position lower than the flame of the parent burner in the secondary air passage, the secondary air before being subjected to combustion of the parent burner can be sufficiently taken in, and the combustion performance is maintained well. Is done.
[0013]
Further, the parent-child burner according to claim 2 of the present invention is set so that the height distance between the lower end of the flame port of the parent burner and the upper end of the flame port of the child burner is 10 mm to 30 mm. The fire transfer between the and the child burners is performed well, and the child burners can also be satisfactorily burned.
That is, if this distance is larger than 30 mm, the fire power of the child burner must be increased to a certain extent in order to make a good fire between the child burner and the parent burner. If the width is smaller than the above range, the supply of secondary air to the child burner may be delayed and the combustion may not be satisfactorily performed when the heating power is increased.
[0014]
Further, in the parent-child burner according to the third aspect of the present invention, the heat power of the entire parent-child burner is adjusted by adjusting the heat power of only the parent burner. That is, the child burner is an ordinary fire burner that always has a constant heating power. For this reason, it is easy to design the positional relationship between the child burner and the parent burner so that a good fire is performed from the child burner to the parent burner.
[0015]
Further, in the parent-child burner according to claim 4 of the present invention, when the heating power is set to the minimum, the parent burner is extinguished, and only the child burner burns. In other words, since the parent burner, which is an inward-facing burner burner that cannot be reduced to a very small thermal power, is extinguished on the way, the minimum thermal power is only the thermal power of the child burner, and the minimum thermal power should be extremely small. Becomes possible.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of a parent-child burner of the present invention will be described below.
[0017]
A table stove for home use as an embodiment of the present invention will be described with reference to FIGS.
In the table stove 1 of the present embodiment, as shown in FIG. 1, an opening 2a is provided in the top plate 2, and a parent and child burner 99 is arranged at the center of the opening 2a. The parent-child burner 99 is composed of a parent burner 3 which is an inward flame port burner which blows out the flame inward, and a child burner 4 which is an outward flame port burner which blows the flame outward.
The parent burner 3, which is an inward burner burner, has a ring-shaped head, and an opening formed at the center of the head is referred to as a central opening 3a. Gotoku 5 on which the cooking pot P is placed is placed on the top plate 2 so as to cover the periphery of the head of the parent burner 3 from above. As will be described later, a child burner 4 which is an outwardly directed flame burner is provided below the central opening 3a of the parent burner 3, and a juice tray 6 is provided around the child burner 4.
[0018]
As shown in FIGS. 1 and 2, the parent burner 3 includes a parent burner main body 3b to which fuel gas and primary air are supplied, and a ring-shaped parent burner head 3c mounted on the parent burner main body 3b. .
The main burner main body 3b includes a mixing pipe section 20 for mixing the fuel gas jetted from the main nozzle 7 and the primary air sucked from the primary air suction port 3d with the jet, and a mounting section for the main burner head 3c. And a main body 30 forming an annular mixture chamber 31.
[0019]
The mixing pipe portion 20 is formed in a tubular shape by facing both the upper plate 21 and the lower plate 22 made of metal formed in a concave shape by press molding and by caulking the ends thereof. A mixing tube side flange portion 23 serving as a connection portion with the main body portion 30 is caulked to the end on the side.
The main body 30 has a ring-shaped upper plate 32 whose upper part is bent inward by press molding, and a distribution plate 34 in which a large number of distribution holes 35 are opened in the ring-shaped flat plate over the entire circumference (FIG. 3). And a lower plate 33 having a ring shape and a concave cross section. Then, the upper plate 32 and the lower plate 33 face each other, and the distribution plate 34 is sandwiched between the upper plate 32 and the lower plate 33 and caulked to form a donut shape having an open upper surface and an inner peripheral side. Further, a communication hole 37 is opened in the lower plate 33, and a main body side flange portion 38 serving as a connection portion with the mixing pipe portion 20 is caulked.
[0020]
A plurality of connection holes 8 are respectively opened in the main body side flange portion 38 and the mixing tube side flange portion 23, and the main body portion 30 and the mixing pipe are connected by connecting the respective connection holes 8 using connection screws 9. The part 20 is connected. At this time, the gas seal is performed by the flange portions contacting each other.
[0021]
The parent burner head 3c is a band-shaped metal having a large number of slit-shaped flame ports 51 (hereinafter, referred to as parent flame ports 51 to distinguish them from the flame ports 4c formed in the child burners 4) by press punching. It comprises a flame port surface portion 50 formed by rolling a plate into a cylindrical shape, and a forging weight member 52 serving as a weight when the parent burner head 3c is placed on the parent burner main body 3b. The weight member 52 is ring-shaped. In addition, when the weight member 52 is placed on the parent burner main body 3b, the weight member 52 comes into contact with the upper surface opening of the parent burner main body 3b to ensure airtightness therein, and also has the parent burner head 3c and the parent burner main body 3b. A cylindrical support member 54 for positioning is vertically attached all around.
Further, the flame face 50 is formed such that the ring diameter becomes larger as it goes upward.
[0022]
Next, the child burner 4 provided below the central opening 3a of the parent burner 3 will be described.
As shown in FIG. 1, the child burner 4 is composed of a child burner head 4a of a forged product having a large number of slit-shaped flame opening grooves on its outer periphery and a child burner main body 4b of a pressed product. By placing the 4a on the child burner main body 4b, a large number of flame holes 4c (hereinafter referred to as child flame holes 4c to distinguish them from the flame holes 51 formed on the parent burner 3) are formed on the outer peripheral edge.
The child burner main body 4b is formed in a tubular shape by facing two metal side plates 4d and 4e formed into a concave shape by press molding and by caulking the ends thereof, and is formed in a tubular shape opposite to the child burner head 4a mounting side. A sub-nozzle 10 to which combustion gas is supplied is mounted at the end on the side. With the ejection of the fuel gas from the child nozzle 10, primary air is sucked from around the fuel nozzle.
An ignition electrode 11 for ignition and a thermocouple 12 for flame detection are installed near the secondary flame outlet 4c.
[0023]
The juice receiving tray 6 disposed around the child burner 4 has an outer peripheral end bent outward to form a mounting edge 6a, and a central hole 6b through which the child burner 4 is inserted is opened at the center. You. In addition, the outer periphery of the central hole 6b is bent upward to prevent the broth from spilling out of the central hole 6b. Three mounting pieces 6c are welded at equal intervals to the bottom surface of the main body 30 of the parent burner main body 3b, and the juice receiving tray 6 is mounted on the mounting piece 6c at the mounting edge 6a. You. In this way, when the juice receiving tray 6 is placed, the central opening 3a of the parent burner 3 is not completely closed, and the secondary air A supply between the juice receiving tray 6 and the inner peripheral surface of the parent burner main body 3b is provided. A gap X is formed.
[0024]
Here, the installation position of the child burner 4 will be described.
FIG. 4 shows the results of measuring the temperature and oxygen concentration distributions inside the parent burner 3 when only the parent burner 3, which is an inward-facing burner burner, is burned without installing the child burner 4. In this experiment, a soup tray without the central hole 6b was used.
The circles in the figure are the measurement points of the temperature and the oxygen concentration. These measurements are carried out at five measurement points provided at intervals of 10 mm in the vertical direction along a central axis G passing through the center of the central opening 3a of the parent burner 3, and further at five measurement points 15 mm in the horizontal direction therefrom. , And at four measurement points 15 mm in the horizontal direction. In addition, the vertical positional relationship of these measurement points is such that three measurement points are arranged at the same height as the lower end of the parent flame port 51, and a row of measurement points is formed at intervals of 10 mm from each other. Relationship.
The temperature and oxygen concentration at the measurement point are shown in the cells at the positions corresponding to the measurement points in the table on the right side in FIG. The numbers in the upper row in one cell in this table indicate the ambient temperature (° C.), and the numbers in the lower row indicate the oxygen concentration (%).
From this experimental result, it can be seen that the oxygen concentration increases as it goes below the parent flame opening 51. The oxygen concentration drops sharply above the lower end of the parent flame opening 51.
In particular, the oxygen concentration was 18% or more below the lower end of the parent flame port 51 by 10 mm or more, and it was confirmed that the region was in a region where good combustion was performed. Therefore, if the child burner 4 is installed such that the upper end of the child flame port 4c is lower than the lower end of the parent flame port 51 of the parent burner 3 by 10 mm or more, the secondary air can be sufficiently taken in and a good combustion state can be maintained. .
[0025]
Further, according to another experimental result, when the distance between the lower end of the parent flame port 51 of the parent burner 3 and the upper end of the child flame port 4c of the child burner 4 becomes 30 mm or more, the child burner 4 must be heated to some extent unless the heat of the child burner 4 is increased. It was confirmed that there was a case where the fire could not be satisfactorily performed from No. 4 to the parent burner 3.
Therefore, the child burner 4 is installed such that the upper end of the child flame port 4c is positioned 10 to 30 mm from the lower end of the parent flame port 51 of the parent burner 3.
[0026]
Next, a fuel gas supply system to the parent and child burners 99 will be described with reference to FIG.
In the gas flow path 60 from the gas connection port of the appliance body to the parent-child burner 99, a magnet safety valve 61 that is opened and held only during the combustion of the parent-child burner 99 by the electromotive force of the thermocouple 12 in order from the upstream, is shown. A main valve 62 is provided for opening and closing the gas flow path 60 in conjunction with a push operation of an ignition button which is not operated.
The gas flow path 60 is branched downstream into a parent gas flow path 63 connected to the parent nozzle 7 and a child gas flow path 64 connected to the child nozzle 10 on the downstream side of the main valve 62. The parent gas flow path 63 is provided with a gas amount control valve 65 that slides in the gas flow path and adjusts the gas flow rate according to the position. The gas amount control valve 65 operates by operating a heating power control lever (not shown).
Further, when the heating power control lever is operated to the minimum heating power, the main gas passage 63 is completely closed and the supply of the fuel gas to the main nozzle 7 is stopped.
[0027]
As described above, the heating power of the parent and child burners 99 is adjusted by adjusting the gas flow to only the parent burner 3. That is, the child burner 4 is an ordinary fire burner that always has a constant heating power. For this reason, it is easy to design the positional relationship between the child burner 4 and the parent burner 3 so that the fire can be satisfactorily performed from the child burner 4 to the parent burner 3.
[0028]
Here, FIG. 6 shows a change in the amount of gas supplied to the parent burner 3, a change in the amount of gas supplied to the child burner 4, and a change in the total amount of gas supplied when the thermal power control lever is operated.
The amount of gas supplied to the sub-burner 4 is always constant at 0.23 kW regardless of the operation of the thermal power control lever. The amount of gas supplied to the parent burner 3 gradually decreases from 4.4 kW to 0.52 kW when the heating power control lever is operated from high heat to low heat, and stops completely when it is moved to the minimum heat power. In other words, the gas supply does not change continuously from 0.52 kW to the stop of the gas supply, but the gas supply stops suddenly when the gas exceeds 0.52 kW. The total supply gas amount is the sum of the supply gas amount to the parent burner 3 and the supply gas amount to the child burner 4, and continuously changes from 4.6 kW to 0.75 kW. It switches to 0.23 kW, which is the amount of gas supplied to the burner 4.
[0029]
The parent burner 3, which is an inward burner burner, has a larger burner outer diameter because the burner outer diameter increases and the distance between the respective master burners 51 needs to be within a possible range of a fire transfer at the time of the minimum thermal power. As a result, the jetting speed of the mixed gas is reduced, and backing and fire extinguishing sounds are easily generated. For this reason, it is not possible to reduce the thermal power much as compared with an outwardly directed flame burner generally used for a household stove (in the parent burner 3 of the present embodiment, the supply gas amount is only up to 0.52 kW. There is a problem that you can not squeeze). On the other hand, in the parent-child burner 99 of the present embodiment, since the supply of fuel gas to the parent burner 3 is stopped at the time of the minimum thermal power, the minimum thermal power is limited to the thermal power of the child burner 4 only. (In the present embodiment, 0.23 kW), and the simmering cooking performance is improved.
[0030]
As shown in FIG. 1, the gotoku 5 on which the cooking pot P is placed has a plurality of L-shaped gotoku claws 5 a on which the cooking pot P is placed, and the inner peripheral edge of the opening 2 a of the top plate 2 and the gotoku claws. 5a is integrally formed with a stake ring 5b serving as a base which stands on the upper surface thereof. That is, the gotoclaw 5a is configured to be supported by the goto ring 5b. The goto ring 5b is a disk having a ring opening 5c formed in the center.
The inner peripheral side of the five-dot ring 5b is inclined downward toward the center of the ring to form an inclined flange 5d. The inclined flange 5d extends until it covers the entire circumference of the head of the parent burner 3, ie, covers the main burner head 3c and the main body 30 of the main burner main body 3b.
Gotoku 5 is placed on top plate 2 by the outer peripheral edge of gotoku ring 5b.
Further, a gap Y for supplying the secondary air A is formed between the parent burner 3, the top plate 2, and the ring 5b.
[0031]
In the table stove 1 having the above-described configuration, the cooking pot P is placed on the goto 5 and an unillustrated ignition button is pressed to ignite the parent and child burners 99 to perform heating cooking. At this time, the child burner 4 is first ignited by the discharge from the ignition electrode 11, and then the fire is transferred to the parent burner 3.
The high-temperature combustion gas generated by the combustion of the parent and child burners 99 moves upward and reaches the bottom of the pot, first strikes the vicinity of the center, spreads to the vicinity of the outer periphery, and heats the cooking pot P well. The combustion exhaust gas after heating the bottom of the pot is discharged to the outside through a gap Z between the goto ring 5b and the cooking pot P. The secondary air for combustion A and B is sucked from the gap X and the gap Y by the draft force generated by this movement.
The child burner 4 is arranged so that the upper end of the child flame port 4c is lower than the lower end of the parent flame port 51 where the flame of the parent burner 3 is formed. The secondary air A before being supplied to the burner 3 is sufficiently taken in, and a good combustion state is maintained. Further, since the parent burner 3 is an inward burner burner and the child burner 4 is an outward burner burner, each burner face comes into contact with the passage of the secondary air A for combustion, and both burners are in contact with each other. Both 3 and 4 make it easier to take in secondary air and improve combustion performance.
[0032]
The heating power is adjusted by operating the heating power adjusting lever according to the degree of cooking. Then, when the throttle operation is performed to the minimum thermal power, the fuel supply to the parent burner 3 is stopped, and combustion is performed only by the child burner 4. Therefore, it is possible to reduce the drawback of the inward flame port burner having poor squeezing performance and to use a very small heating power, thereby improving the simmering cooking performance.
Further, when the heating power is increased by operating the heating power control lever from the minimum heating power, the fuel gas is again supplied to the parent burner 3, the fire burns from the child burner 4, and the fuel is burned by both the parent burner 3 and the child burner 4.
Since the parent burner 3 is an inward burner burner and the child burner 4 is an outward burner burner, the two burners face each other. The fire transfer to the parent burner 3 is performed well. For this reason, it is only necessary to provide the ignition electrode 11 on the child burner 4 side, and it is possible to suppress the cost of manufacturing the parent-child burner 99.
[0033]
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention.
[0034]
【The invention's effect】
As described in detail above, according to the parent-child burner according to claim 1 of the present invention, the parent burner is an inward-facing burner burner, and the child burners are disposed facing each other as an outward-facing burner burner. Good fire transfer between both burners. Therefore, if the ignition device is installed on one of the burners, the production cost can be reduced.
In addition, by providing the child burner below the parent flame opening in the secondary air passage, secondary air before being used for combustion of the parent burner can be sufficiently supplied to the child burner, and the combustion performance is improved. . In addition, since the parent burner is an inward burner burner and the child burner is an outward burner burner, each burner surface comes into contact with the secondary air passage, and the combustion performance is further improved.
[0035]
Further, according to the parent-child burner according to the second aspect of the present invention, both the fire transfer performance and the combustion performance can be favorably maintained.
[0036]
Furthermore, according to the parent-child burner according to the third aspect of the present invention, since the child burner is a normal-fire burner having no change in thermal power, the child burner and the parent burner can be satisfactorily fired from the child burner to the parent burner. Easy to design the positional relationship with.
[0037]
Further, according to the parent-child burner according to claim 4 of the present invention, since the inward-facing burner burner with poor throttling performance is completely extinguished during the heat power adjustment, only the child burner which is the outward-facing burner burner with the minimum heating power is required. It is possible to make the thermal power very small. For this reason, the simmering cooking performance is improved, and delicious cooking can be performed.
[Brief description of the drawings]
FIG. 1 is a sectional view of a table stove as an embodiment.
FIG. 2 is a sectional view of a parent burner according to the embodiment.
FIG. 3 is a top view of a distribution plate according to the embodiment.
FIG. 4 is an explanatory diagram showing the results of measuring the distribution of temperature and oxygen concentration inside the parent burner when only the parent burner is burned.
FIG. 5 is a schematic diagram of a fuel gas supply system according to the embodiment.
FIG. 6 is a graph showing changes in the amount of gas supplied to the parent burner, changes in the amount of gas supplied to the child burners, and changes in the total amount of gas supplied when the thermal power is adjusted.
FIG. 7 is a cross-sectional view of a gas stove as a conventional example.
FIG. 8 is an explanatory diagram showing a state of contact between a flame formed on an inwardly directed flame port burner and a cooking pot. (A) When the burner outer diameter is large, (b) When the burner outer diameter is small FIG. 9 is a cross-sectional view of a parent-child burner as a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 ... Parent burner, 3a ... Central opening, 4 ... Child burner, 4c ... Child flame port, 31 ... Mixture chamber, 50 ... Flame port surface part, 51 ... Parent flame port, 60 ... Gas flow path, 63 ... Parent gas flow Road, 64: child gas flow path, 65: gas amount control valve, 99: parent and child burner.

Claims (4)

In a parent-child burner including a large-fire parent burner and a small-fire child burner,
The parent burner forms an annular air-fuel mixture chamber, and blasts the air-fuel mixture from a number of flame ports arranged in an inner peripheral surface of the air-fuel mixture chamber. An inward burner burner that takes in secondary air,
The child burner is an outwardly directed flame burner in which a number of flames are radially arranged on the outer peripheral side, and is arranged in the secondary air passage surrounded by the air-fuel mixture chamber of the parent burner. A parent-child burner, wherein the upper end of the flame port of the child burner is lower than the lower end of the flame port of the parent burner. The parent-child burner according to claim 1, wherein the height distance between the lower end of the flame port of the parent burner and the upper end of the flame port of the child burner is 10 mm to 30 mm. A thermal power control device for controlling the thermal power,
Gas amount adjusting means for adjusting only the amount of gas supplied to the parent burner without changing the amount of gas supplied to the child burner by the heat power adjusting operation by the heat power adjusting operation device. The parent-child burner according to claim 1 or 2. The amount of gas supplied to the parent burner decreases as the thermal power is reduced by the thermal power control operator, and when the thermal power is adjusted to the minimum thermal power, the gas supply to the parent burner is stopped. The parent-child burner according to claim 3.

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